Okay, so I'm not sure exactly why I thought of this, but here is what I'm wearing for Halloween. It is for real creepy, not just Halloween creepy, so you may not want to read this. I'll leave some space just in case.
I took a ring from my mother's jewelry collection. It's a poison ring, where the "stone" flips up and there's a little hole inside for you to casually poison people's drinks with Iocane powder. Except I didn't put Iocane powder in the hole. I put a small piece of grey, charred bone that didn't entirely turn to ash when mom was cremated. I am otherwise dressed perfectly normally, just with this morbid piece of costume jewelry.
Slightly ghoulish, certainly, but I find it oddly comforting and also in the spirit of the season.